    
    ### True values specification     
    alpha.true  = c(0.1,0.5)
    beta.true   = c(0,-0.5)
    gamma.true  = c(0.1,-0.5)  
    zeta.true   = c(0,-1)
    eta.true    = c(-0.5,1)
    params.true = list(alpha.true=alpha.true, beta.true=beta.true,
                       gamma.true=gamma.true, zeta.true=zeta.true,
                       eta.true = eta.true)

    set.seed(0)
    n  = 1e8
    x1 = rep(1,n)  #intercept term
    x2.ind       = rbinom(n,1,0.5)
    x2           = ((-1)^x2.ind) * runif(n,0.5,1)
    x  = cbind(x1,x2)
    Delta.true = mean(tanh(x %*% alpha.true))
    rm(n, x1, x2.ind, x2, x)

